Perfumes and scents catch our attention even from a distance. People can generally smell our perfume the minute we spray it on, even if they are not in the room.
How is that?
This is because of the process of diffusion that happens as soon as the perfume is released into the air. Being a compressed chemical, once the perfume is sprayed, it turns into gas and its particles get mixed with the air particles very quickly. It is this tendency of gases to quickly occupy any volume or space available to them that is called diffusion. Gas particles are loosely packed and hence are free to move about rapidly in all directions, which make them eventually spread out and fill the surroundings along with the air.
For the same reason, we don’t have to use our hands to get the smell everywhere, including our body. It gets blended on its own.
This is precisely what happens when perfume is sprayed and why its fragrance spreads fast.
Liquids too undergo diffusion, but it happens at a slower pace as the molecules in liquids are more closely packed together, which gives them less space to move about.